Who knows anything about building cabs?

Discussion in 'Amps and Cabs [BG]' started by NHLfan2010, Oct 9, 2011.

  1. NHLfan2010


    Aug 12, 2010
    I'm talking specifics here. Not just any 6 pieces of wood screwed together with some speakers in them, but how do different things affect the sound. I have done a little bit of research about this but haven't been able to find a whole lot.

    I have heard that ported cabs are really the way to go in bassland, but I'm not totally sure how a ported cab works. Are the ports essentially just large(ish) holes in the wood or are they like plastic tubes that go in several inches?(one site made it seem that way) Also, what is the difference between porting like that and porting with a small long slot along the bottom of the front?

    Primarily, I was wanting to build this cab to be as small as possible and portable, but I don't know if making it shallow vs deep (depth-wise) will affect its tone.

    Also, what does the resonance of the cab have to do with things? How do I make sure the cab will be able to cover a good frequency range (especially on the low end, since I play a 5 string and the fundamental frequency of a low B is 30hz).

    Another thing I have been tossing around is speaker configuration. Wanting to make it portable I was thinking 2x10, or maybe 2x12. But I was just tonight trying to imagine a 15 and a 6 cab, that might be able to be small. Haven't sized any of those up exactly yet, just thinking. What are your favorite portable cab configurations?

    Actual construction, I am not worried about too much. I just want to know everything about design of amp cabs before I build it. Anything else that I didn't necessarily ask about but has to do with cabinet design, throw at me. I love learning, and especially learning about things I love.

    Kind of a longer post, thanks for reading it all and for your comments.
  2. iammr2


    Jun 10, 2002
  3. B-string

    B-string Supporting Member

    Look at the stickies on top of the forum, lots of good info there. Including a free design program. You need to decide on a specific speaker FIRST, then build a cab for it. Very low frequencies are not that important (as the stickies will let you know). Small cab that goes remotely deep....is not going to happen.
    Start reading and you will learn a lot!
  4. First off, this would be a good place:


    Another place to start would simply be the Eminence website. They give box designs for every speaker.

    Speaker Detail | Eminence Speaker

    (not necessarily that speaker... it was just a way to show the 'spec sheet' and 'cabinet design' at the top)

    There is a TON of good info on there among other places on TalkBass. Ports are generally plastic tubes that go into a cabinet to "tune" the cabinet to a specific frequency. The results between tube ports and shelf ports are the same, they are just a different way of porting the cab.

    Most people are into small, portable cabs today, but you can't have little, low, AND loud. You have to pick the two you prefer or make a compromise. If you want a very portable cab, it won't be too big, so I won't do HUGE bass. But I'm sure you already knew that.

    If you're using 2x12s or 2x10s, make sure to use the same speaker. If you're doing a 15 and 6" combination, you have to worry about crossovers. So make sure you're ready to tackle that challenge as well.

    Have fun with it. It's definitely not always cheaper building your own cab, but I agree with you.... it's fun and very enjoyable playing on your finished product.
  5. Mike Arnopol

    Mike Arnopol Inactive Supporting Member Commercial User

    Jan 4, 2005
    Owner of MAS Soundworks
    go to the fearful site---- greenboy.us

    a wealth of info
  6. Hi.

    Since we bassist are always low on power, the horn loaded design makes the most sense by being the most efficient design. Look up BFM for that.

    Basically the ports are just holes in a box, tuning it according to Helmholz resonator principles. The reality however is much, much more complicated.

    That will rule out every efficient cab, including the horn loaded and most of the ported designs.

    With ported cabs, the resonance is everything. If You're aiming to f3 of 30Hz, You'll need a huge cab to reproduce that with any significant SPL. You'll also need several thousand watts of power to drive that cab. Better aim a lot higher with f3, and concentrate on reproducing the harmonics clearly.

    fEarful threads are a good read, as suggested earlier.

  7. Passinwind

    Passinwind I know nothing. Commercial User

    Dec 3, 2003
    Columbia River Gorge, WA.
    Owner/Designer &Toaster Tech Passinwind Electronics
    Read this (all of it!).
  8. billfitzmaurice

    billfitzmaurice Commercial User

    Sep 15, 2004
    New Hampshire
    Owner, Bill Fitzmaurice Loudspeaker Design

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